Industrial lift trucks



Dec. 19, 1967 Filed June l, 1966 R. GOODACRE INDUSTRIAL LIFT TRUCKS I 2 Sheets-Sheet l Fg. f.

Dec. 19, 1967 R. GOODACRE INDUSTRIAL LIFT TRUCKS 2 Sheets-Sheet 2 Filed June 1, 1966 United States Patent() 3,358,791 INDUSTRIAL LIFT TRUCKS Ronald Goodacre, Basingstoke, Engiand, assigner to Lansing Bagnali Limited, Basingstoke, England, a British company Fiied .lune 1, 1966, Ser. No. 554,434 Claims priority, application Great Britain, June 1, 1965, 23,375/ 65 9 Claims. (Cl. 187-9) ABSTRACT OF THE DISCLGSURE An industrial lift truck comprises a load carriage having two pairs of rollers for engagement with the anges of two channel guide members, means being provided to prevent lateral movement of the rollers relative to the channel portions of the guide members, which means comprise, in respect of one roller of each pair of rollers, a step projecting inwardly from the web of the channel portion of the associated guide member and contacting the roller and in respect of the other roller of each pair of rollers, a flange projecting from the periphery of the roller and contacting the free edge of one of the flanges of the channel portion.

This invention relates to industrial lift trucks and provides an industrial lift truck comprising two upright guide members braced together in spaced apart relation one with the other, each member having a channel portion facing towards the channel portion of the other member, a load-carriage extending at least between the guide members, two pairs of rollers fixed to the load carriage, the rollers of each pair being located one above the other and extending into and being in contact with the inside of the flanges of the channel portion of one of the guide members, the carriage and the guide members being free to slide relatively to each other, characterised in that the axes of the rollers are perpendicular to the web of the channel portion of the associated guide member but, in the normal intended alignment of the carriage to the vertical, displaced to one side of the longitudinal axis of the channel portion the axis of each top roller being displaced forwardly of the axis of the channel portion and the axis of each bottom roller being displaced rearwardly of the axis of the channel portion, and in that means are provided to prevent lateral movement of the rollers relative to the channel portions of the guide members, which means comprise, in respect of one roller of each pair of rollers, a step projecting inwardly from the web of the channel portion of the associated guide member and contacting the roller and in respect of the other roller of each pair of rollers, a flange projecting from the periphery of the roller and contacting the free edge of one of the flanges of the channel portion.

This construction thus allows a clearance between each roller and one of the flanges of the channel portion, the flange being a different ange in respect of each roller, and at the same time does not allow the load-carriage to tilt forward out of its intended alignment to the vertical on a load being applied to the carriage.

It is preferred that the axes of the rollers are displaced from the longitudinal axis of the channel portion of the associated guide member by an equal amount.

It is also preferred that the said step of each channel portion is located adjacent the flange of the channel portion which contacts the roller in contact with the step.

One flange of each channel portion is preferably shorter than the other ilange ofthe channel portion, the free edge of the longer flange being the said free edge which is contacted by the flange of the flanged roller. This longer flange is also preferably the iiange of the channel portion that contacts the periphery of the anged roller.

It is preferred that the rollers which lie in contact with the steps as aforesaid are the bottom rollers and the rollers which are each provided with a ange as aforesaid are the top rollers.

Preferably each roller is provided with means for accurately locating the roller in a lateral direction and for locking the roller in that position.

By way of example, a truck in accordance with the invention will now be described with reference to the accompanying drawings in which:

'FIGURE 1 is a plan View of the masts and lifting carriage of the truck;

FIGURE 2 is a section of the part of the truck shown in FIGURE l along two horizontal planes, the left-hand part being a section through the left-hand top support roller for the lifting carriage and the right-hand part being a section through the right-hand bottom support roller for the lifting carriage; and

FIGURE 3 is a section along the line 3-3 in FIG- URE 1.

With reference to the drawings, the truck is provided with a load lifting mechanism comprising a pair of forwardly extending forks 5t) (partially shown in FIGURES 1 and 3) attached in normal manner to the top and bottom edges of a vertical lifting carriage 10. The forks 50 are adjustable along the carriage 10 and lateral movement of each fork is precluded by a removable pin 51 engaging in a recess 52 in the top edge of the lifting car'- riage. The carriage l0 is capable of being raised and lowered on a first pair of upright guide members 11, commonly known as an inner mast, braced together in parallel spaced relation one with the other, which members are in turn capable of being raised in sliding engagement with a second pair of upright guide members 12, conimonly known as an outer mast, also braced together in parallel spaced relation one with the other, each member being located on the outside of the adjacent member 11 of the inner mast. A jack 40 is provided for effecting movement of both the carriage 10 relative to the inner mast and of the inner mast relative to the outer mast. The arrangement employed, in this example, is known as a partial-lift arrangement in which extension of the jack 40 effects an initial upward sliding movement of the carriage relative to the inner mast. When buffers 43, 44 provided on the carriage (see especially FIGURE 1) engage the underside of the part 41 of the inner mast, further extension of the jack 40 will raise the inner mast in addition to effecting further raising of the carriage. This arrangement is widely used in the art and need not be further described except -in connection with details which specifically affect the subject of this invention.

Each member 11 of the inner mast is basically of channel-section, which channel is directed towards the channel of the other member for co-operation therebetween with two pairs of rollers 15, 16 mounted one above the other on bars 13 secured to the back side of the lifting-carriage 10, which rollers allow relative vertical movement between the carriage and the inner mast.

Further pairs of rollers 17, 18, 46 are also provided between the guide members o-f the inner mast and the guide members of the outer mast, which latter members are also of channel section. The rollers 17 are mounted on the members 11 of the inner mast for engagement in the channel of the adjacent member 12 of the outer mast and the rollers 18, 46 are mounted on an upward extension 47 of the associated member 12 of the outer mast for engagement with an outwardly projecting flange 20 provided on the adjacent member 11 of the inner mast. Rubbing pads 48, 49 are also provided which, in co-operation with the aforesaid rollers 17, prevent the guide members 11 of the inner mast moving laterally relative to the guide members 12 of the outer mast during movement of the inner mast, which rubbing pads 48, 19 are mounted on the guide members 11 and engage the inner web face of the guide members 12 (see FIGURE 2). Further rubbing pads (not shown) are also provided between adjacent surfaces of the outer mast guide members 12 and the inner mast guide members 11, which pads are fixed to the forward flanges of the guide members 12.

Each roller 15, 16 is, as shown, mounted on a ball bearing 21 which is in turn mounted on a spindle 22 fixed to the associated bar 13 secured to the lifting carriage Each roller 15, 16 and the associated guide members 11 of the inner mast are also designed to generate the minimum amount of friction during relative movement of the lifting carriage and the inner mast and yet` also maintain the rigidity and stability of the lifting carriage of the truck.

This result is achieved in two ways, the first of which is by locating each roller 15, 16 with its axis perpendicular to the longitudinal axis of the corresponding guide member 11 but displaced to one side thereof, the axis of each roller 15, which is the top roller of each pair of rollers 15, 16, being displaced towards the forward flange 23 of the guide member and the axis of each roller 16, which is the bottom roller being displaced towards the rear flange 24 of the guide member thereby providing a clearance between each roller 16 and the forward flange 23 of the corresponding guide member 11 and between each roller and the rear flange 24 of the corresponding guide member 11. By this construction there is no tendency for the lifting carriage to tilt in a forward direction when load is applied to the forks of the lifting carriage and at the same time the minimum amount of friction is generated during relative movement of the rollers 15, 16 and the guide members 11.

The second way is in connection with the tendency lfor the lifting carriage to move laterally especially when the load is unevenly placed on the forks. In respect of each of the bottom rollers 16, the corresponding guide member is undercut, eg. by milling, to leave a small step 25 against which the roller is pressed, the step 25 being adjacent the rear flange 24 of the corresponding guide member 11, whereby the surfaces of the roller which contact the rear flange and the step member are adjacent one another. In addition each top roller 15 is provided with an outwardly projecting flange 26 which contacts the edge 27 of the forward flange 23 of the corresponding guide member. Also, so that the flange 26 of the roller will not contact the corresponding edge of the rear flange 24, the rear flange is shorter, or is cut back to make it shorter, than the forward flange 23, thereby creating a clearance between the flange 24 and the flange 26 of the roller. Again the surfaces of each roller 15 which contact the surfaces of the guide member are adjacent one another. Hence by use of the step 25 and the flange 26 there is no tendency for the lifting carriage to move laterally and yet also the minimum amount of friction is generated during relative movement of the rollers and the guide members.

So that each roller 15, '16 can be readily held in contact against either the corresponding step 25 or edge 27 of the corresponding guidemember 11, the spindle 22, on which the roller bearing kof each roller 15, 16 is mounted, is provided with a groove 28 extending helically around the periphery of the spindle for co-operation with a bolt 29. The end of the spindle 22 is also provided with a pair of holes 30 whereby it may be rotated to move the roller towards or away from its corresponding guide member, the bolt 29 being located in fixed relation to the bar 13 through which the spindle 22 passes. The bar 13 is also provided with a slot 31 so that tightening of the bolt may cause the spindle to be locked against rotation relative to the bar 13, the position of the spindle being such that the surfaces of the roller are in contact, but do not bind, with the step 25 or the edge 27 of the guide member, as the case may be.

This invention is not limited to the features of the truck as described above. For example, the steps 25 and the flanges 26 provided for preventing lateral movement of the lifting carriage 19 may be reversed so that the bottom rollers 16 are provided with the flanges and the top rollers 15 contact the steps.

Also similar means to those provided for reducing the friction generated by the rollers 15, 16 during relative movement of the inner mast and the lifting carriage and yet retaining the stability of the truck, may be pro-vided in respect of the rollers 17, 13 between the inner mast and the outer mast.

I claim:

1. An industrial lift truck comprising two upright guide members braced together in spaced apart relation one with the other, each member having a channel portion facing towards the channel portion of the other member, a load-carriage extending at least between the guide members, two pairs of rollers fixed to the load-carriage, the rollers of each pair being located yone above the other and extending into and being in contact with the inside of the flanges of the channel portion of one of the guide members, the carriage and the guide members being free to slide relatively to each other, characterised in that the axes of the rollers are perpendicular to the web of the channel portion of the associated guide member but, in the normal intended alignment of the carriage to the vertical, displaced to one side of the longitudinal axis of the channel portion, the axis lof each top roller being displaced forwardly of the `axis of the channel portion and the axis of each bottom roller being displaced rearwardly of the axis of the channel portion, and in that means are provided to prevent lateral movement of the rollers relative to the channel portions of the guide members, which means comprise, in respect of one roller of each pair of rollers, a step projecting inwardly from the web of the channel portion of the associated guide member and contacting the roller and in respect of the other roller of each pair of rollers, a flange projecting from the periphery of the roller and contacting the free edge of the flanges of the channel portion.

2. A truck as claimed in claim 1 in which the axes of the rollers are displaced from the longitudinal axis of the channel portion of the associated guide member by an equal amount.

3. A truck as claimed in claim 1 in which the said step of each channel portion is located adjacent the flange of the channel portion which contacts the roller in contact with the step.

4. A truck as claimed in claim 1 in which one flange of each channel portion is shorter than the other flange of the channel portion, the free edge of the longer flange being the said free edge which is contacted by the flange of the flanged roller.

5. A truck as claimed in claim 4 in which this longer flange is also the flange of the channel portion that confacts the periphery of the flanged roller.

6. A truck as claimed in claim 1 in which the rollers which lie in yContact with the steps as aforesaid are the bottom rollers and the rollers which are each provided with a flange as aforesaid are the top rollers.

7. A truck as claimed in claim 1 in which each roller is provided with means for accurately locating the roller in a lateral direction and for locking the roller in that position.

8. A truck as claimed in claim 7 in which each roller 1s mounted for rotation on a spindle and in which the said locating means comprise a helical circumferential groove provided on the spindle and engaged by the shank of a pin or bolt, which pin or bolt is held against movement in a direction parallel to the axis of the spindle.

9. A truck as claimed in claim 8 in which the spindle is received within a split socket and the bolt is operable to close the socket into clamping engagement with the spindle in any required position of adjustment thereof.

References Cited UNITED STATES PATENTS EVON C. BLUNK, Primazy Examiner. H. C. HORNSBY, Assistant Examiner. 

1. AN INDUSTRIAL LIFT TRUCK COMPRISING TWO UPRIGHT GUIDE MEMBERS BRACED TOGETHER IN SPACED APART RELATION ONE WITH THE OTHER, EACH MEMBER HAVING A CHANNEL PORTION FACING TOWARDS THE CHANNEL PORTION OF THE OTHER MEMBER, A LOAD-CARRIAGE EXTENDING AT LEAST BETWEEN THE GUIDE MEMBERS, TWO PAIRS OF ROLLERS FIXED TO THE LOAD-CARRIAGE, THE ROLLERS OF EACH PAIR BEING LOCATED ONE ABOVE THE OTHER AND EXTENDING INTO AND BEING IN CONTACT WITH THE INSIDE OF THE FLANGES OF THE CHANNEL PORTION OF ONE OF THE GUIDE MEMBERS, THE CARRIAGE AND THE GUIDE MEMBERS BEING FREE TO SLIDE RELATIVELY TO EACH OTHER, CHARACTERISED IN THAT THE AXES OF THE ROLLERS ARE PERPENDICULAR TO THE WEB OF THE CHANNEL PORTION OF THE ASSOCIATED GUIDE MEMBER BUT, IN THE NORMAL INTENDED ALIGNMENT OF THE CARRIAGE TO THE VERTICAL, DISPLACED TO ONE SIDE OF THE LONGITUDINAL AXIS OF THE CHANNEL PORTION, THE AXIS OF EACH TOP ROLLER BEING DISPLACED FORWARDLY OF THE AXIS OF THE CHANNEL PORTION AND THE AXIS OF EACH BOTTOM ROLLER BEING DISPLACED REARWARDLY OF THE AXIS OF THE CHANNEL PORTION, AND IN THAT MEANS ARE PROVIDED TO PREVENT LATERAL MOVEMENT OF THE ROLLERS RELATIVE TO THE CHANNEL PORTIONS OF THE GUIDE MEMBERS, WHICH MEANS COMPRISE, IN RESPECT OF ONE ROLLER OF EACH PAIR OF ROLLERS, A STEP PROJECTING INWARDLY FROM THE WEB OF THE CHANNEL PORTION OF THE ASSOCIATED GUIDE MEMBER AND CONTACTING THE ROLLER AND IN RESPECT OF THE OTHER ROLLER OF EACH PAIR OF ROLLERS, A FLANGE PROJECTING FROM THE PERIPHERY OF THE ROLLER AND CONTACTING THE FREE EDGE OF THE FLANGES OF THE CHANNEL PORTION. 